The present disclosure relates to an image forming device, and particularly, to a technology for cooling a paper sheet and preventing water droplets from adhering.
As a general image forming device, a device using an electrophotographic method is well known. The electrophotographic method includes five processes, for example, a charging process in which a photoreceptor having no electrical charge is uniformly charged, an exposure process in which laser light is emitted to an electrically charged photoreceptor surface based on a copy document, and a latent image of the document is formed on the photoreceptor surface, a developing process in which the latent image is visualized with toner, a transfer process in which a toner image formed by visualization is transferred to a recording medium such as a paper sheet placed on a transfer belt, and a fixing process in which the transferred toner image is fixed to the recording medium.
Here, in the fixing process, when the toner is fixed to the paper sheet, heat above a high temperature of 100 to 180° C. and pressure are applied to the paper sheet by a fixing unit. However, when the paper sheet that underwent the fixing process is discharged to a discharge tray, and several tens of sheets of paper overlap at a high temperature, heat of the paper sheet does not dissipate, and the toner that was fixed once is attached to other overlapping sheets of paper. Such a situation is highly likely to occur as a printing speed increases. When the printing speed increases, a fixing temperature increases, the discharged sheets of paper are successively stacked, and a time for which the discharged paper sheet is exposed to outside air decreases.
In addition, when heat is applied to the paper sheet, moisture contained in the paper sheet is evaporated to water vapor, and becomes water droplets that adhere to a component configured to convey the paper sheet, and the water droplets accumulate on the component. Therefore, when the accumulated water droplets adhere to the paper sheet, there is a problem in that a printed image is blurred. In particular, since the paper sheet does not pass a conveying path or a conveying roller (for example, a switchback roller) for double-sided printing when single-sided printing is performed, water droplets are likely to accumulate.
As technologies for preventing water droplets from accumulating, for example, there is a technology for condensing and collecting generated water vapors. A technology for releasing the generated water vapors to an atmosphere is also proposed. In addition, recently, it is considered to be effective to provide a cooling fan and apply cooling air to a location that needs to be cooled.